1. a) The acute standard (AS) for the chemical constituents listed in subsection (e) must not be exceeded at any time except as provided in subsection (d).
2. b) The chronic standard (CS) for the chemical constituents listed in subsection (e) must not be exceeded by the arithmetic average of at least four consecutive samples collected over any period of four days, except as provided in subsection (d). The samples used to demonstrate attainment or lack of attainment with a CS must be collected in a manner that assures an average representative of the sampling period. For the chemical constituents that have water quality-based standards dependent upon hardness, the chronic water quality standard will be calculated according to subsection (e) using the hardness of the water body at the time the sample was collected. To calculate the attainment status of chronic standards, the concentration of the chemical constituent in each sample is divided by the calculated water quality standard for the sample to determine a quotient. The water quality standard is attained if the mean of the sample quotients is less than or equal to one for the duration of the averaging period.
3. c) The human health standard (HHS) for the chemical constituents listed in subsection (f) must not be exceeded, on a 12-month rolling average based on at least eight samples, collected in a manner representative of the sampling period, except as provided in subsection (d).

4. d) In waters where mixing is allowed under Section 302.102, the following apply:

   1. 1) The AS must not be exceeded in any waters except for those waters for which a zone of initial dilution (ZID) applies under Section 302.102.
   2. 2) The CS must not be exceeded outside of waters in which mixing is allowed under Section 302.102.
   3. 3) The HHS must not be exceeded outside of waters in which mixing is allowed under Section 302.102.

5. e) Numeric Water Quality Standards for the Protection of Aquatic Organisms

   Constituent	AS (µg/L)	CS (µg/L)
   Arsenic (trivalent, dissolved)	340 X 1.0*=340	150 X 1.0*=150
   Benzene	4200	860
   Cadmium (dissolved)	eA+B ln(H) X {1.138672-[(ln(H))(0.041838)]}*, where A=-2.918 and B=1.128	eA+B ln(H) X {1.101672-[(ln(H))(0.041838)]}*, where A= -3.490 and B=0.7852
   Chromium (hexavalent, total)	16	11
   Chromium (trivalent, dissolved)	eA+B ln(H) X 0.316*, where A=3.7256 and B=0.8190	eA+B ln(H) X 0.860*, where A=0.6848 and B=0.8190
   Copper (dissolved)	eA+B ln(H) X 0.960*, where A=-1.645 and B=0.9422	eA+B ln(H) X 0.960*, where A=-1.646 and B=0.8545
   Cyanide**	22	10
   Ethylbenzene	150	14
   Fluoride (total)	eA+B ln(H), where A=6.7319 and B=0.5394	eA+B ln(H), but must not exceed 4.0 mg/L, where A=6.0445 and B=0.5394
   Lead (dissolved)	eA+B ln(H) X {1.46203-[(ln(H))(0.145712)]}*, where A=-1.301 and B=1.273	eA+B ln(H) X {1.46203-[(ln(H))(0.145712)]}*, where A=-2.863 and B=1.273
   Manganese (dissolved)	eA+B ln(H) X 0.9812*, where A=4.9187 and B=0.7467	eA+B ln(H) X 0.9812*, where A=4.0635 and B=0.7467
   Mercury (dissolved)	1.4 X 0.85*=1.2	0.77 X 0.85*=0.65
   Nickel (dissolved)	eA+B ln(H) X 0.998*, where A=0.5173 and B=0.8460	eA+B ln(H) X 0.997*, where A=-2.286 and B=0.8460
   Toluene	2000	600
   TRC	19	11
   Xylene(s)	920	360
   Zinc (dissolved)	eA+B ln(H) X 0.978*, where A=0.9035 and B=0.8473	eA+B ln(H) X 0.986*, where A=-0.4456 and B=0.8473

   where:

   µg/L	=	microgram per liter
   H	=	Hardness concentration of receiving water in mg/L as CaCO3
   ex	=	base of natural logarithms raised to the x-power
   ln(H)	=	natural logarithm of hardness in mg/L as CaCO3
   *	=	conversion factor multiplier for dissolved metals
   **	=	standard to be evaluated using either of the following USEPA approved methods, incorporated by reference at 35 Ill. Adm. Code 301.106: Method OIA-1677, DW: Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry, January 2004, Document Number EPA-821-R-04-001; or Cyanide Amenable to Chlorination, Standard Methods 4500-CN-G (40 CFR 136.3)

6. f) Numeric Water Quality Standard for the Protection of Human Health

   Constituent	HHS (µg/L)
   Benzene	310
   Mercury (total)	0.012
   Phenols	860,000

   where:

   µg/L

   =

   microgram per liter

7. g) Numeric Water Quality Standards for Other Chemical Constituents

   1. h) Concentrations of other chemical constituents in the South Fork of the South Branch of the Chicago River (Bubbly Creek) must not exceed the following standards:

      CONSTITUENT	CONCENTRATION (mg/L)
      Ammonia Un-ionized (as N*)	0.1
      Arsenic (total)	1.0
      Barium (total)	5.0
      Cadmium (total)	0.15
      Chromium (total hexavalent)	0.3
      Chromium (total trivalent)	1.0
      Copper (total)	1.0
      Cyanide (total)	0.10
      Fluoride (total)	15.0
      Iron (total)	2.0
      Iron (dissolved)	0.5
      Lead (total)	0.1
      Manganese (total)	1.0
      Mercury (total)	0.0005
      Nickel (total)	1.0
      Oil, fats and grease	15.0**
      Phenols	0.3
      Selenium (total)	1.0
      Silver	1.1
      Zinc (total)	1.0
      Total Dissolved Solids	1500

      * For purposes of this Section, the concentration of un-ionized ammonia must be computed according to the following equation:

      

      where:

      X	=
      U	=	Concentration of un-ionized ammonia as N in mg/L
      N	=	Concentration of ammonia nitrogen as N in mg/L
      T	=	Temperature in degrees Celsius

      ** Oil must be analytically separated into polar and non-polar components if the total concentration exceeds 15 mg/L. In no case may either of the components exceed 15 mg/L (i.e., 15 mg/L polar materials and 15 mg/L non-polar materials).

   Concentrations of the following chemical constituents must not be exceeded except in waters for which mixing is allowed under Section 302.102.

   Constituent	Unit	Standard
   Chloride	mg/L	500
   Iron (dissolved)	mg/L	1.0
   Selenium (total)	mg/L	1.0
   Silver (dissolved)	µg/L	eA+B ln(H) X 0.85*, where A=-6.52 and B=1.72
   Sulfate (where H is ≥ 100 but ≤ 500 and C is ≥ 25 but ≤ 500)	mg/L	[1276.7+5.508(H)-1.457(C)] X 0.65
   Sulfate (where H is ≥ 100 but ≤ 500 and C is ≥ 5 but < 25)	mg/L	[-57.478 + 5.79(H) + 54.163(C)] X 0.65
   Sulfate (where H > 500 and C ≥ 5)	mg/L	2,000

   where:

   mg/L	=	milligram per liter
   µg/L	=	microgram per liter
   H	=	hardness concentration of receiving water in mg/L as CaCO3
   C	=	chloride concentration of receiving water in mg/L
   ex	=	base of natural logarithms raised to the x-power
   ln(H)	=	natural logarithm of hardness in milligrams per liter
   *	=	conversion factor multiplier for dissolved metals

(Source: Amended at 47 Ill. Reg. 4437, effective March 23, 2023)